package com.wyc.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.wyc.dto.Result;
import com.wyc.entity.VoucherOrder;
import com.wyc.mapper.VoucherOrderMapper;
import com.wyc.service.ISeckillVoucherService;
import com.wyc.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wyc.utils.RedisIdWorker;
import com.wyc.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.*;

import java.util.List; // Ensure this import is present

/**
 * <p>
 * 服务实现类
 * </p>
 *
 **/
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder>
        implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;
    /*
     * 加载Lua脚本
     */
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    // 创建线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    // 使用注解让这个类一加载完就看开始执行
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    /**
     * 队列名
     */
    private static final String queueName = "stream.orders";
;    // 内部类
    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true){
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );

                    // 2、判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        // 2.1 消息获取失败，说明没有消息，进入下一次循环获取消息
                        continue;
                    }
                    // 3、消息获取成功，可以下单
                    // 将消息转成VoucherOrder对象
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder =  BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 获取成功下单
                    handleVoucherOreder(voucherOrder);
                    // 4、ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());

                  }catch (Exception e){
                    log.error("处理订单异常",e);
                    // 处理异常消息
                    handlPendingList();

                }
            }
        }

        private void handlPendingList() {
            while (true){
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );

                    // 2、判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        // 2.1 消息获取失败，说明没有消息，说明pending-list没有异常消息
                        break;
                    }
                    // 3、消息获取成功，可以下单
                    // 将消息转成VoucherOrder对象
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder =  BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 获取成功下单
                    handleVoucherOreder(voucherOrder);
                    // 4、ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());

                }catch (Exception e){
                    log.error("处理pending-list订单异常",e);
                    try {
                        Thread.sleep(50);
                    }catch (InterruptedException e1){
                        e1.printStackTrace();
                    }
                }
            }
        }
    }
//    // 内部类
//    private class VoucherOrderHandler implements Runnable {
//        @Override
//        public void run() {
//            while (true){
//                try {
//                    // 获取队列的订单信息
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    // 创建订单
//                    handleVoucherOreder(voucherOrder);
//                }catch (Exception e){
//                    log.error("处理订单异常",e);
//
//                }
//            }
//        }
//    }

    private void handleVoucherOreder(VoucherOrder voucherOrder) {
        // 获取用户ID
        Long userId = voucherOrder.getUserId();
        // 创建锁对象
        RLock lock = redissonClient.getLock("lock:order" + userId);
        // 获取锁,设置锁的时间
        boolean isLock = lock.tryLock();
        if (!isLock) {
            // 获取锁失败,因为是异步不做任何返回只做提示
            log.error("不允许重复下单");
            return;
        }
        try {

            proxy.createVoucherOrder(voucherOrder);
        } finally {
            // 释放锁

            lock.unlock();
        }
    }

    // 获取主线程的代理
    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 订单id
        long orderId = redisIdWorker.nextId("order");
        // 执行脚本
        Long result =  stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),userId.toString(),
                String.valueOf(orderId)
        );
        // 判断结果是否为0
        int r = result.intValue();
        if(r != 0){
            //不为0代表没有资格
            return Result.fail(r == 1? "库存不足" : "不能重复下单" );
        }

        // 获取代理对象(事务)
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        return Result.ok(orderId);
    }
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        // 获取用户
//        Long userId = UserHolder.getUser().getId();
//        // 执行脚本
//        Long result =  stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),userId.toString()
//        );
//        // 判断结果是否为0
//        int r = result.intValue();
//        if(r != 0){
//            //不为0代表没有资格
//            return Result.fail(r == 1? "库存不足" : "不能重复下单" );
//        }
//        // 为0则有购买资格，把下单信息保存在阻塞队列
//        // 创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // 订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        // 用户id
//        voucherOrder.setUserId(userId);
//        // 代金卷id
//        voucherOrder.setVoucherId(voucherId);
//        // 获取代理对象
//        // 获取代理对象(事务)
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//
//        // 把信息存入阻塞队列
//        orderTasks.add(voucherOrder);
//        return Result.ok(orderId);
//    }
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//
//        // 查询优惠卷
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        // 判断是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            // 尚未开始
//            return Result.fail("秒杀尚未开始");
//        }
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            // 已经结束
//            return Result.fail("秒杀已经结束");
//        }
//        // 判断是否充足
//        if (voucher.getStock() < 1) {
//            // 库存不足
//            return Result.fail("库存不足");
//        }
//        Long userId = UserHolder.getUser().getId();
//        // 创建锁对象
//        //SimpleRedisLock lock = new SimpleRedisLock("order" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order" + userId);
//        // 获取锁,设置锁的时间
//        boolean isLock = lock.tryLock();
//        if (!isLock) {
//            // 获取锁失败,返回错误或重试
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            // 获取代理对象(事务)
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } finally {
//            // 释放锁
//
//            lock.unlock();
//        }
//    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 一人一单
        Long userId = voucherOrder.getUserId();

        // 查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId().toString()).count();
        // 判断是否已经购买过
        if (count > 0) {
            // 用户已经购买过
            log.error("一人限购一次");
            return;
        }
        // 扣减库存(乐观锁)
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1 ") // set stock = stock - 1
                .eq("voucher_id", voucherOrder.getVoucherId().toString()).gt("stock", 0) // where voucher_id = voucherId and stock > 0
                .update();
        if (!success) {
            // 扣减失败
            log.error("库存不足");
            return;
        }

        save(voucherOrder);

    }
}
